1. Field of the Invention
This invention relates to curable epoxy resin compositions. More particularly it relates to 4,4,6-trimethylhexahydropyrimidine as a curing agent.
2. Description of the Prior Art
Epoxy resins constitute a broad class of polymeric materials having a wide range of physical characteristics. The resins are characterized by epoxide groups which are cured by reaction with certain catalysts or curing agents to provide cured epoxy resin compositions with certain desirable properties. Conventional curing agents include such compounds as polyamines, polycarboxylic acids, anhydrides and Lewis acids.
Preimpregnates are formed by partially curing a polyepoxide. The partially reacted epoxy system is stabilized before complete curing by means such as refrigeration. The partially reacted material may be formed into a required shape, with for example a filament, and the cure completed with heating.
U.S. Pat. Nos. 4,146,714 and 4,212,843 describe the synthesis of 4,4,6-trimethylhexahydropyrimidine, the epoxy resin curative of the present invention.